A 3-star nin is 110% and 115% at 4 stars

so the trick is to first subtract the 10% then add the 15%

Life: 47873*1.15/1.1 = 50049 >>> 2176 gained

Attack: 31672*1.15/1.1 = 33111.6 >>>1439 gained

Ninjutsu: 34728*1.15/1.1= 36306.5 >>>1578 gained

Defense: 19299*1.15/1.1 = 20176 >>>877 gained

Resistance: 21420*1.15/1.1 = 22393 >>>973 gained